1. Field of the Invention
The present invention relates to a rotary kiln that performs a heat treatment on a process material while transferring the process material in an axial direction, and to a product manufactured by the rotary kiln.
2. Description of the Related Art
A rotary kiln includes a shell that rotates about its own axis (see Japanese Patent Application Publication No. 2008-128492 (JP-A-2008-128492), for example). FIG. 14 is a perspective view of a rotary kiln disclosed in JP-A-2008-128492. As shown in FIG. 14, a rotary kiln 100 includes a shell 101, a heating section 102, and a platform 103. A pair of front and rear rollers 103a is disposed on the left side of the upper surface of the platform 103. Also, a pair of front and rear rollers 103b is disposed on the right side of the upper surface of the platform 103. A pair of left and right tires 101a and 101b is disposed on the outer peripheral surface of the shell 101. A gear 101c is disposed on the right side of the tire 101b. The heating section 102 covers the body portion of the shell 101.
The tire 101a is placed on the pair of rollers 103a. Also, the tire 101b is placed on the pair of rollers 103b. When a rotational force is applied to the gear 101c, the tire 101a rolls on the pair of rollers 103a. Also, the tire 101b rolls on the pair of rollers 103b. This allows the shell 101 to rotate about its own axis.
A process material is transferred inside the rotating shell 101 from the right side (supply side) to the left side (discharge side). At this time, the process material is heated by heat of the heating section 102. In this way, the rotary kiln 100 performs a heat treatment on the process material.
In the case of the rotary kiln 100 according to the related art, it is necessary to mount the tires 101a and 101b on the outer peripheral surface of the shell 101 in order to allow rotation of the shell 101 while securely supporting a rotation axis thereof. In addition, it is necessary to mount the gear 101c on the outer peripheral surface of the shell 101 in order to transmit a rotational force.
Depending on the material of the shell 101, however, it may be difficult to mount these members on the outer peripheral surface of the shell 101. For example, in the case where the shell 101 is made of a ceramic and the tires 101a and 101b and the gear 101c are made of a metal, it is necessary to mount the members on the outer peripheral surface of the shell 101 by tightening the members on the shell 101. In this case, if the tightening force is loose, the members may slip with respect to the shell 101. On the contrary, if the tightening force is large, the force that compresses the shell 101 from the radially outer side to the radially inner side may be strong. Thus, it may be difficult to mount the tires 101a and 101b and the gear 101c depending on the material of the shell 101. Thus, the rotary kiln according to the related art has low versatility for the material of the shell.
The shell 101 is designed to have a diameter set in accordance with the amount of production and the characteristics of the process material. For example, in the case where the amount of production of the process material is set to be much, the shell 101 is designed to have a large diameter. On the contrary, in the case where the amount of production of the process material is set to be little, the shell 101 is designed to have a small diameter.
In the case of the rotary kiln 100 according to the related art, however, a change in diameter of the shell 101 involves a change in dimensions of the tires 101a and 101b, the gear 101c, the rollers 103a and 103b, and so forth. For example, an increase in diameter of the shell 101 involves an increase in diameter of the tires 101a and 101b and the gear 101c. An increase in diameter of the shell 101 also involves an increase in interval between the pair of rollers 103a and interval between the pair of rollers 103b. On the contrary, a decrease in diameter of the shell 101 involves a decrease in diameter of the tires 101a and 101b and the gear 101c. A decrease in diameter of the shell 101 also involves a decrease in interval between the pair of rollers 103a and interval between the pair of rollers 103b. Thus, the rotary kiln 100 according to the related art has low versatility for the diameter of the shell 101.